Dental crown remover



April 29, 1930. Q FLAGsTAD ET AL 1,756,245

DENTAL CROWN REMOVER Filed Oct/10,. 1927 2 Sheets-Sheet 1 April 29, 1930. O FLAGSTAD E 1 AL DENTAL CROWN REMOVER 2 2 Sheets-Sheep 2 Filed Oct. 10

INVENTORS 0.4.FLA657'AD F .5 .LEE

AT ORNEY the following specification,

Patented Apr. 29, 1930 CUNITED, TA ES PATENT ewes OSCAR A. FLAGSTAD, orvrrnnnnroms, AND RUEZBENG. LEE, or norm/IAN,

" MINNESOTA DENTAL cnown rmlvrovrin Application fi ledf October 10, 1927'. Serial N in. 225,298.

This invention relates to dental crown re- I movers, and the primary object is to provide means of a novel, efficient and practical nature forremoving the gold crowns of'teeth 5 without destroying their usefulness, so that a crown may be replaced upon the tooth after the latter has been treated or repaired, as is frequently necessary. Further and more specific objects will be disclosed in the course of reference being 7 had to the accompanying drawings, wherein:

Fig. 1 is an enlarged elevation of a preferred form of our improvedcrown remover. Fig. 2 is a sectional plan view on the'line 2'-'2in'Fig.1. f

Fig. 3 is an elevation of a modified form of the device as shown in Fig. 1.

Fig. 4 is a similar elevation showing'a further modification of the device, and with fractional parts broken away.

fied orm of the device, with fractional parts broken away and insection.

Fig. 6 is a central sectional elevation of the crown removeras shown in Fig. l andon the line 6-6 in that figure.

Fig. 7 is a greatly enlarged perspective giew of a still further modified form of the evice.

line 8 8 in Fig.7.

Fig. 9 is a sectional elevation'as on the line 99 in Fig. 8.

l Referring to the drawings more particular- 1y and by reference characters, the device shown in Figs. 1, 2 and 6, will'first be de scribed as follows:

A and B designate'a pair of awsor claws the lower ends of which are so formed that they may grip the crown to ,be removed, or may be engaged under the lower edges of the V crown if so desired. The upperends of the;

jaws are pivoted, as at (1 in the outer bifurof the yoke for engagement in arecess H4, for' forcing the jaws A and B'together in a clamp 1 Fi 5 is an elevation of a still further modicrown by a screw L that spreads the jaw Fig. '8 is a sectlonal elevationas on the the jaw members are forcibly spread by a cated ends of a cross bar D. A. forked bar.

actionupon the crown. The cross bar..D is

provided,'with' a forcing screw I, having a pin J formed at its lower end, which extends into a hole, that has previously beendrill'ed in the face of the crown, to engage against the top of the tooth. It will thus be seen that after the crown has first been drilled to provide a hole for the pin J, the jaws A, B are clamped upon the crown and as the screw I is forced down upon the tooth the crown will be freed from the cement by which it is secared to the tooth. In order that the device may be more conveniently manipulated or held in place by the dentist it may be provided with a handle K (see Figs. 1 and 6).

In the modification shown in Fig. 3, a pair ofjaws'A and B are pivoted, as at C to a'connecting link D which accommodates a- .forclng screw I in the-same manner as the link D'retains the screw I in Figs. 1 and 2. Inthi's device the jaws are forced against the portions above the fulcrums 0 This screw L threads in a lug M that is free to rock on the member B while the other end of the mechanism including'three links N and O,

'pivotally connected to each other and, to the jawsas at-P. The tooth engaging screw '1 in this case, is relatively long, is provided with a pair of nuts Q an'dR, and is further provid' ed, between the nut R and the link 0, with a ,compression spring S. The nut Q, serves as a lock nut for the nut It which, when screwed down on the screw Iiincre'ases the clamping pressure of the. jawsnpon the crown. l/Vhen v this device is applied to'a crown, it will be noted that as the -forcingscrew I which is threaded in D is screweddown, it will also increase the tension on the spring S, thus tightening the clamp on the crown. As the working stroke of the screw is very short it will not excessively increase the clamping action, but, on the'other hand, it will materially increase the clamping grip at the moment of the jaws.

The device shown in Figs. 7-9, while more complicated than the others described, is par- 7 ticularly valuable in that it may be operated by the dentist entirely from outside of the patients mouth. j

The jaws 1O andr ll are pivoted in the bifurcated ends of a link member 12. The forcing screw 13 does not rotate, in this case, but is moved up and down by a bevel pinion 14 in which it is threaded, and which in turn is journaled with abridge link 12. The pinion 14 meshes with a pinion 15 carried on a shaft 16 having a turning head or knob 17 I as The shaft 16 is journaled in a yoke 18, the

arms of which are trunnioned, as at -19,'so

that the shaft 16 may be swung from one side to another in the patients mouth as may be found necessary. A look nut 20 may be used to secure the shaft 16 with respect to the yoke 18.

The jaws 101l are opened and closed by a reversely threaded screw 21, that screws into a pair ofcollars 22 that are pivotally carried by the upper ends of the jaws. The screw 2lthas a worm gear 23, driven by a worm 24 upon the inner end of a shaft 25 having a turning knob 26 at its outer end. The worm 24 and shaft 25 are held in operative position by a bearing member 27 that is carried on'the screw 21. The outer ends of the shafts 16 and 25 are preferably connected by a link member 28, one end of which is provided with a slot 29 to permit some play, for adjustments, for instance, when the shaft 16 is moved toward either side. It will thus be seen that the jaws 1011 are opened and closed by the knob 26, and that the actual crown removing operation is effected through turning of the knob 17.

, It is understood that suitable modificatio ns may be made in the general design and structural details of the invention as herein shown and described, provided, however, that said modifications come within the spirit and V scope of the appended claims.

scribed our invention, what we claim to be Having now therefore fully shown and de- V 1. A-dental crown remover comprising a 7 pair of, jaws adapted to grip the sides of the crown, a link pivotally connecting the jaws, a

' T i tooth engagingscrew threaded in and operating through the link between the jaws, and

pair of jaws adapted to grip the sides of the crown, a link pivotally connecting the jaws, a tooth engaging screw operating through the link between the jaws, and means associated with the said screw for effecting a clamping action to the jaws, whereby the screw will be advanced and the jaws will be closed simultaneously, said means including a" spring which will cushion the clamping ac tion of the jaws upon the crown.

4. A dental crown remover comprising a pair of jaws adapted to grip the sides of the crown, a link and a lever acting mechanism connecting the jaws, a screw threaded to screw in said link and between the jaws," and means including anadjustable spring on the screw for engaging the mechanism to clamp the jaws upon a crown.

5. A dental crown remover comprising a pair of jaws adapted to grip the sides of the crown, a transversely disposed link connecting at its ends to the jaws, a screw threaded in the link for engagement with a tooth under the crown, and means adjustable independently of or together with the screw, for effecting a clamping action to the jaws.

6. A dental crown remover comprising a pair of jaws adapted to grip the sides of the crown, a link connecting the jaws, a screw threaded in the link for engagement with a tooth under the crown, and means adjustable independently of or together with the screw, for efiecting a clamping action to the jaws, said means includinga spring, and a mem ber threaded on the screw. V i

7. A dental crown remover comprising a pair of, jaws adapted to grip the sides of the crown, a link connecting the jaws, a screw threaded in the link for engagement with a tooth under the crown, and means adjustable independently of or together with the screw,

for effecting a clamping action to the jaws,

OSCAR A. FLAGSTAD. RUEBEN G. LEE. 

